Radiation streaming through a duct, a guide or a penetration may be described analytically following the Sullivan systematics. This description depends on the physical parameters of the duct (length, diameter, number of legs), on the material surrounding the duct, on the radiation type and energy and on the radiation incident angle. Whereas the parameters of the duct (length, diameter, number of legs) are explicit in the Sullivan description, the information on the radiation type, energy and incident angle, as well as the information on the materials, is collected in a single empirical parameter: the coefficient parameter K. There are experimental data available describing the K parameter, however these data are incomplete — and they are not covering all the cases relevant for the ESS. Moreover, there is no analytical formula available to determine K as a function of given variables (radiation type, energy, incident angle and scattering material). The scope of this project is to determine such an analytical formula via Monte Carlo methods and to validate it against existing experimental data.

A motivated student, with a good background in nuclear physics and some knowledge of programming, can complete this thesis project in one semester (30 ECTS).